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<Title>Boost Graph Library: is_straight_line_drawing</Title>
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<H1><tt>is_straight_line_drawing</tt></H1>

<p>
<pre>
template &lt;typename Graph, typename GridPositionMap, typename VertexIndexMap&gt;
bool is_straight_line_drawing(const Graph& g, GridPositionMap drawing, VertexIndexMap vm);
</pre>

<p>
If <tt>drawing</tt> is a property map modeling the PositionMap
concept, <tt>is_straight_line_drawing</tt> returns true exactly when no two of
the line segments induced by edges in the graph under <tt>drawing</tt>
intersect. This function works correctly in the presence of self-loops and
parallel edges, and can be used to verify the output of the function
<tt>
<a href="straight_line_drawing.html">chrobak_payne_straight_line_embedding.</a>
</tt>

<p>

<h3>Complexity</h3>

Runs in time <i>O(n log n)</i> on a planar graph with <i>n</i> vertices.

<H3>Where Defined</H3>

<P>
<a href="../../../boost/graph/is_straight_line_drawing.hpp"><TT>boost/graph/is_straight_line_drawing.hpp</TT></a>

<h3>Parameters</h3>

IN: <tt>Graph&amp; g</tt>

<blockquote>
An undirected graph. The graph type must be a model of <a
href="EdgeListGraph.html">Edge List Graph</a>
</blockquote>

IN: <tt>PositionMap</tt>

<blockquote>
A <a href="../../property_map/doc/LvaluePropertyMap.html">Readable LValue Property
Map</a> that models the Position Map concept. The Position Map concept requires
that the value mapped to be an object that has members <tt>x</tt> and
<tt>y</tt>. For example, if <tt>p</tt> models PositionMap and <tt>v</tt>
is a vertex in the graph, <tt>p[v].x</tt> and <tt>p[v].y</tt> are valid
expressions. The type of <tt>x</tt> and <tt>y</tt> must be implicitly
convertable to <tt>std::size_t</tt>.
</blockquote>

IN: <tt>VertexIndexMap vm</tt>

<blockquote>
A <a href="../../property_map/doc/ReadablePropertyMap.html">Readable Property Map</a> that maps vertices from <tt>g</tt> to distinct integers in the range <tt>[0, num_vertices(g) )</tt><br>
<b>Default</b>: <tt>get(vertex_index,g)</tt><br>
</blockquote>

<H3>Example</H3>

<P>
<a href="../example/straight_line_drawing.cpp"><TT>examples/straight_line_drawing.cpp</TT></a>

<h3>See Also</h3>

<p>
<ul>
<li><a href="planar_graphs.html">Planar Graphs in the Boost Graph Library</a>
<li><a href="straight_line_drawing.html">
<tt>chrobak_payne_straight_line_drawing</tt></a>
</ul>

<br>
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Copyright &copy; 2007 Aaron Windsor (<a href="mailto:aaron.windsor@gmail.com">aaron.windsor@gmail.com</a>)
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